What is this? Answered
We spent a week at a beach house. In the photo, you see a device attached to a door. There were several of them attached to doors throughout the house. It's a hollow steel ball attached to an arm, which was attached to the door. It could move back and forth like a pendulum, but it rubs against the door and doesn't move freely. You can see the rub marks on the door. So it didn't swing by simply opening or closing the door. This photo was taken in 2003 and I still don't know what it is or what purpose it served. If you know what it is, please leave a comment.